Endovascular Stenting of Obstructed Right Ventricle–to–Pulmonary Artery Conduits

Abstract

Background-The optimal treatment for dysfunctional right ventricle-to-pulmonary artery (RV-PA) conduits is unknown.Limited follow-up data on stenting of RV-PA conduits have been reported. Methods and Results-Between 1990 and 2004, deployment of balloon-expandable bare stents was attempted in 242 obstructed RV-PA conduits in 221 patients (median age, 6.7 years). Acute hemodynamic changes after stenting included significantly decreased RV systolic pressure (89Ϯ18 to 65Ϯ20 mm Hg, PϽ0.001) and peak RV-PA gradient (59Ϯ19 to 27Ϯ14 mm Hg, PϽ0.001). There were no deaths, and, aside from 5 malpositioned stents requiring surgical removal, there were no serious procedural complications. During follow-up of 4.0Ϯ3.2 years, 9 patients died and 2 underwent heart transplantation, none related to catheterization or stent malfunction. During 155 follow-up catheterizations in 126 patients, the stent was redilated in 83 patients and additional stents were placed in 41. Stent fractures were diagnosed in 56 patients (43%) and associated with stent compression and substernal location but did not cause acute hemodynamic consequences. By Kaplan-Meier analysis, median freedom from conduit surgery after stenting was 2.7 years (3.9 years in patients Ͼ5 years), with younger age, homograft conduit, conduit diameter Յ10 mm, diagnosis other than tetralogy of Fallot, Genesis stent, higher prestent RV:aortic pressure ratio, and stent malposition associated with shorter freedom from surgery. Tricuspid regurgitation and RV function did not change between stent implantation and subsequent surgery. Conclusions-Conduit

Coronary compression caused by stenting a right pulmonary artery conduit

“…A good practice is to preballoon the lesion. Low pressure ballooning delineates the waist to accurately and safely position a stent [6]. High pressure ballooning in combination with coronary or other angiography allows assessment of the possible effects of stent expansion to threatened structures [5,7].…”

“…These conduits may become restrictive due to peal formation, shrinkage, external compression, or somatic growth. Endovascular stenting of pulmonary artery conduits has been shown to be effective and safe [1,2]. Percutaneous pulmonary valve implantation will further increase the number of conduits being stented [3].…”

NuMED covered cheatham‐platinum stent™ for the treatment or prevention of right ventricular outflow tract conduit disruption during transcatheter pulmonary valve replacement

“…The lifespan of bioprosthetic valves or RVOT conduits is limited by progressive obstruction and/or regurgitation due to a variety of factors including mechanical fatigue, immunologic reaction to the surgical implant, extrinsic conduit compression and somatic outgrowth in growing children. Endovascular treatment using balloon dilatation and bare stent implantation has been shown to extend conduit lifespan and reduce a patient's need for repeated open heart surgeries [1]. While resolving the problem of conduit obstruction, bare stent placement leads to creation or exacerbation of pulmonary regurgitation.…”

Prevention and Treatment of Thrombosis in Pediatric and Congenital Heart Disease

“…637,638 Since then, their use in children has expanded considerably, now playing a major role in the management of almost all stenotic vascular lesions in children, [639][640][641] including branch pulmonary artery stenosis, 641,642 systemic venous obstructions, 643 systemic arterial stenosis such as coarctation of the aorta, [644][645][646] pulmonary vein stenosis, patent ductus arteriosus, 647 and surgical conduits or homograft prostheses. [648][649][650] Stents are also used to maintain vascular patency of the ductus arteriosus in selected conditions. 647,651 Although for most of these lesions in-stent restenosis and thrombosis are very rare, 641,652 specific lesions are considered to be at higher risk of thrombosis, especially those associated with passive nonpulsatile flow, very small vessels, or lesions at recanalization of previously thrombosed vessels.…”